Pour the Elderflower Lemonade and the lemon juice together into their own container. The Lemonade is organic, but I thought it would be a nice touch to add fresh squeezed juice to bring out the flavor. Pour about 3 tablespoons of this mixture into a Champagne flute. Pour in enough cava to fill the glass 3/4 full...or to your liking. Swirl gently. Drop a few raspberries in that thing, say cheers, and sip!